<!DOCTYPE html>
<html>

<head lang="en">
    <meta charset="UTF-8">
    <title></title>
    <style type="text/css">
    * {
        margin: 0;
        padding: 0;
    }
    
    ul {
        list-style: none;
    }
    
    .wrap {
        width: 330px;
        height: 30px;
        margin: 100px auto 0;
        padding-left: 10px;
        background-image: url(imgs/bg.jpg);
    }
    
    .wrap li {
        background-image: url(imgs/libg.jpg);
    }
    
    .wrap > ul > li {
        float: left;
        margin-right: 10px;
        position: relative;
    }
    
    .wrap a {
        display: block;
        height: 30px;
        width: 100px;
        text-decoration: none;
        color: #000;
        line-height: 30px;
        text-align: center;
    }
    
    .wrap li ul {
        position: absolute;
        top: 30px;
        display: none;
    }
    </style>
    <script src="../jquery-1.11.1.min.js"></script>
    <script>
    $(document).ready(function() {
        // 动画效果
        $(".wrap > ul > li").mouseenter(function () {
            // $(this).children("ul").show(1000);

            // 不传参数：跟"normal"这个参数 作用相同
            // $(this).children("ul").slideDown(1000);

            // stop() 方法：停止动画
            //$(this).children("ul").stop().show(1000);

            $(this).children("ul").stop().fadeIn(1000);
        });

        $(".wrap > ul > li").mouseleave(function () {
            //$(this).children("ul").hide(1000);
            // $(this).children("ul").slideUp("fast");
            //$(this).children("ul").stop().hide("fast");
            $(this).children("ul").stop().fadeOut(1000);
        });
    });
    </script>
</head>

<body>
    <div class="wrap">
        <ul>
            <li>
                <a href="javascript:void(0);">一级菜单1</a>
                <ul>
                    <li><a href="javascript:void(0);">二级菜单1</a></li>
                    <li><a href="javascript:void(0);">二级菜单2</a></li>
                    <li><a href="javascript:void(0);">二级菜单3</a></li>
                </ul>
            </li>
            <li>
                <a href="javascript:void(0);">一级菜单2</a>
                <ul>
                    <li><a href="javascript:void(0);">二级菜单1</a></li>
                    <li><a href="javascript:void(0);">二级菜单2</a></li>
                    <li><a href="javascript:void(0);">二级菜单3</a></li>
                </ul>
            </li>
            <li>
                <a href="javascript:void(0);">一级菜单3</a>
                <ul>
                    <li><a href="javascript:void(0);">二级菜单1</a></li>
                    <li><a href="javascript:void(0);">二级菜单2</a></li>
                    <li><a href="javascript:void(0);">二级菜单3</a></li>
                </ul>
            </li>
        </ul>
    </div>
</body>

</html>
